Moisture tester



Nov. 19, 1929. M. L. MUELLER MOISTURE TESTER Filed Aug. 29, 1927 3 Sheets-Sheet l I INVENTOR. flak/T2 Z. Ml/EL LER A TTORNE Y.

Nov. 19, 1929. M. L. MUELLER MOISTURE TESTER F l g 1927 5 Sheets-Sheet 2 INVEN TOR.

E L L E m 2 6% W R Y. 08 M Nov. 19, 1929. MUELLER 1,736,505

MOISTURE TESTER File g 1927 3 Sheets-Sheet 3 latented Nov. 19, 1929 UNITED STATES PATENT OFFICE IOBITZ L. MUELLER, OF SEATTLE, WASHINGTON, ASSIGNOR TO NORTHWEST BLOWER IILN COMPANY, OF PORTLAND, OREGON, A CORPORATION OF WASHINGTON MOISTURE TESTER Application filed Augult 29, 1827. Serial No. 216,124.

This invention relates to a moisture tester, and has for its object to provide an improved device of this character, constructed in such manner as to render it possible to ascertain the moisture content of a given material with marked rapidity and efiiciency.

In many industries there is need of de-- tel-mining the moisture content of materials being used. This is accomplished by weighing the material, or a sample of it, in its original state, then drying such sample until the moisture in it is entirely (within practical limits) removed, then reweighing it and by using the two weights secured, calculating the original amount of moisture in it in terms of percentage of either dry or original weight.

Many materials dry slowly in ordinary ovens, making it necessary that several. hours elapse between the time the first weight and the second weight is taken. This is due to the fact that in ordinary ovens, the heat oi the oven is transmitted to the sample bymeans of hot air surrounding the sample, this air carrying the heat from heating units to the material being dried. Heat from the air enters the material slowly with the result that the moisture in it, evaporates slowly. It would be desirable in order to transfer heat at the highest possible rate into such mate rial, to have hot plates directly contact with it, but this is not practical because the hot plates would, under usual working conditions', scorch or burn the material. Further, the moisture from the material would escape but slowly as no room would be left between the hot plates and the surface of the material for ventilation, or air circulation. Evaporation of moisture under such conditions, is very slow.

To overcome this delay and reduce the time required to secure a test of this nature, I have devised the combination oven and scale of the present invention.

In many cases, it is desirable to secure an average of the moisture content of several samples, for test, to avoid getting hold of samples that are not typical. With this device this average may be secured very rapidly by weighing all samples together, then Fig. 2 is a side view of one form or" the invention, with the scale mechanism diagrammatically illustrated,

Fig. 3 is a face view of one of the drying plates, hereinafter described,

Fig. 4 is a vertical sectional view through one or" said plates,

Fig. 5 is a diagrammatic side view illustrating another form of the invention,

Fig. 6 is a diagram of the electrical connections of the heating units of the drying plates, and

Fig. '3' is a diagrammatic view of still another form of the invention.

Like numerals designate corresponding parts in all of the fi ures of the drawings.

' In each form of t e invention an electrical- 1y heated ovenA. is su ported by a scale. In the particular form oi ovens, chosen for the urposes of illustration, a central fixed drymg plate 5 projects upwardly from a pan 6, that is carried by a vertically movable stem 7. Arms 8, disposed at the opposite ends of the pan 6 are pivoted at their lower ends to said pan at 9, and are pivoted at their upper ends 10, to self-adjusting drying plates 11, 12, 13 and 14. Springs 15 tend to move the self-adjusting drying plates towards the cen-- tral fixed plate 5.

By referring to Figs. 3 and 4 it will be seen that each drying plate consists of the two side members 16 and 17, which are held in spaced relation to each other by spacing membars 18 and 19. Electrical heating elements 20 are disposed within the hollow interiors of the several plates, and serve to heat said plates to the desired degree.

Those faces of the heating plates which are to come in contact with the material to be heated are so formed as to present a multiplicity of pyramidal bosses -a, the result being that only the extremities of these bosses come into actual .contact with the material to be heated, and a large number of channels are left for the circulation of air, by which the moisture, driven off from the material being heated, is conducted away from said material asrapidly as it is released. This combined action of direct contact heating, and eflicient air circulation and ventilation, results in drying material in a few minutes,wh'ere,' under the old method, hours would be required.

The electrical connections for the several heatin units of the plates are diagrammatically s own in Fig. 6, from which it will be seen that, the several heating units 20 are connected in multiple, and are served by the common leads 21 and 22. These leads extend the invention. In each case the vertical stem 7 is supported by a knife-edge 26 upon one end of a beam 27, that is ivoted intermediate its ends upon a knife-e ge 28. The stem 7 is hollow and the leads 21 and 22 pass therethrough. These leads are provided with convolutions, or other flexible connections 21, 22 at the pivot point or knife-edge 28, so that the beam may move freely without interference by the electrical connection.

In each of the forms shown a tare beam 29 is supported from the main beam 27.

In the form of the invention illustrated in Fig. 2 that end of the beam 27 that is remote from knife-edge 26 is connected to the core 30 of a solenoid magnet, the windings of which are indicated at 31. These windings are in series with a choke coil or rheostat 32. A standard attachment socket 33 is connected by a lead 34 with one side of an ammeter 35. The other side of this ammeter is connected by a lead 36 with the coil 31. The other side of the attachment plug is connected by a lead 37 with the movable contact member 38 of the rheostat. The degree to which the action of the solenoid resists downward movement of the oven A, and the material carried thereby, will be determined by the strength of the current flowing in the solenoid coil 31. The strength of the current flowing in the solenoid coil may be varied by adjustment of the movable member 38 of the rheostat. In use, the movable member 38 will be adjusted until the action of the solenoid just balances the beam 27 If the ammeter 1,7se,5os

35 be graduated in terms of weight, for exam le, the reading of its needle, if compared wit some previously taken reading, Wlll indicate how much weight has been lost by the material in oven A, under the drying action.

.The structure illustrated in Fig. 7 is very similar to that illustrated in Fig. 2, though, in this case, the solenoid ma net and associated parts, has been replace by a conventional counter-balancing weight and scale pan 40, which bears throu h a knife-edge 41, upon the left hand end of the standard or main beam 27 In the form of the invention illustrated in Fig. 5 the left hand end of the main beam 27 acts through knife-edge 41, and rod 42, upon the counter-balancing beams 44, 45 and 46. These beams are rigidly connected with each other, and, as a whole, are pivotally mounted at 47. The beams 44 and 45 carry the conventional counter-poises .48, said beams being graduated in the standard manner, in terms of weight, While the beam 46 may be graduated, as in standard percentage scales to read in terms of percentage direct. It will be apparent that by providin the plurality of drying plates, as illustrate in Fig. 1, I produce, in eflect, an oven having several compartments, and where it is desired to measure the average moisture content of several samples, as hereinbefore described, these several samples may be placed in the several compartments of the oven, weighed in their wet condition and, after they have been thoroughly dried, may be weighed again, the difference in weight indicating the amount of moisture that has been removed and, consequently, indicating the general moisture content of the mass from which the samples were taken.

It is clear that many ways may easily be devised by those skilled in the art, for mounting an oven to be moved bodily with a scale element.

Therefore, it is to be understood that the invention is not limited to the particular embodiment thereof, shown in the accompanying drawings, but that it includes within its purview whatever changes fairly come within either the terms or the spirit of the appended claims.

Having described my invention, what I claim is:

1. The combination with a movable scale element, of a heatin unit mounted thereon and movable therewit and means for heating said unit while in position upon the scale element, said unit being ofa nature to bodily receive samples to be simultaneously heated and weighed.

2. The combination with a movable scale element, of an electrical heating unit mounted thereon and movable therewith, and electrical connections leading to the heating unit through the scale element for electrically heating the same.

memos 3. The combination with a movable scale element, of a plurality of heating plates mounted directly thereon, and formmg a series of heating compartments between them.

- 4. The combination with a movable scale element, of a plurality of heating plates mounted thereon, movable toward and from each other, and presenting a series of heating compartments between them.

5. The combination with a movable scale element, of a plurality of electrical heating units mounted thereon, and a common current supply element for said heating units leading through the scale element.

6. The combination with a movable scale element, of a plurality of flat electricall heated plates, swinging arms pivoted to sai plates, and by which said plates are supported from the scale element, and spring means tending to move said plates toward each other.

7 The combination with a scale beam pivoted intermediate its ends, of an electrically heated element, supported from one end of said beam, and measuring elements connected to the other end of said beam.

8. The combination with a scale beam, pivoted intermediate its ends, of a hollow stem supported from one end of said beam, electrical connections leading through said stem, electrically heated plates u 11 said stem to which current is conducted y said electrical connections, and measuring mechanism connected to the other end of said scale beam.

9. The combination with a movable scale element, of a plurality of hollow flat plates supported thereon, an electrical heating coil in each of said lates, said coils being connected in multip e, and common supply leads for said coils extending through the movable scale element.

In testimony whereof I afiix m si ature.

MORITZ L. ER. 

